one man brake bleed help (trying a gravity bleed?)

[columnshift]

Okay, so i'm finally resuming my dodge caravan brake repair starting with the wheel cylinders, except that means i'll have to bleed it afterwards.

I looked up and saw people talking about 'gravity bleeding' where you jack up the front higher than the rears (do you jack anything if bleeding the fronts??) and just open the bleed screws for awhile while constantly topping off the master cyl with more fluid. They say by the time you put a pint through one brake you should be done.

Sounds good to me! I dont think this van has had brake fluid changed in over a decade anyway (even though it's mostly sat) so kills two birds with one stone. Is this dumb, or should I be doing it differently, or do you have any other comments about thsi process though?


What kind of test would you recommend (on a deserted road obviously, there's literally a long gravel unused road just off my street for miles) to verify whether the brakes are properly bled afterwards? Or just as long as the brake pedal feels hard afterwards it should be fine?

I'd like to this over the building a one man brake bleeder stuff esp when normally in the future I should have a 2nd person to help again. (I actualy had one I built before for a different car, it's buried somewhere in the garage, i'd have to remodify it for the dodge to fit the cap, and after I used it I realized I never solved the problem of how do I clean out the old likely water-logged fluid by now when it's got many feet of hose on it to begin with still lined with the old fluid)

 

[slacktide_bitog]

You should get speed bleeders. They include a check valve that lets air out but not in

 

[SHOZ]

Some brakes bleed easily with the gravity method. Some don't.

I use a one man bleeder. You need some 1/4" ID clear hose. Three small hose clamps. A short 1/4" bolt and a clear bottle and a cap.

Put bolt in end of hose. Put hose clamp on to secure it. Cut a 1/2" vertical slit immediately above the bolt. Drill a hole the OD size of the hose in the cap.

Thread hose up through the cap leaving enough hose so the bolt sits on the bottom of the bottle with the cap on. Use a hose clamp or cable tie at the top under the cap so the hose does not pull out.

Use a hose clamp on the bleeder screws to secure the hose.

Open the bleeder a flat or so and pump away. Once enough fluid is in the bottle and covers the slit there will not be any air sucked up.

 

[HerrStig]

One can buy a bleeder kit for less than 10 bucks. Hose, fittings, and bottle with magnet to hold it to the fender.

 

[columnshift]

Originally Posted By: HerrStig
One can buy a bleeder kit for less than 10 bucks. Hose, fittings, and bottle with magnet to hold it to the fender.


I tried to use one of those once, theyre a total joke. >_> If the fitting doesn't pop out of where it pushes into the bleed screw the tiny bottle fills up too fast to be any good.


I was hoping for someone that had experience gravity bleeding could offer comments since I need to replace fluid anyways.

 

[BigD1]

I just gravity bleed until it starts flowing, and then bleed them while another person works the pedal. Last time I changed a rear brake hose it seemed like three minutes or longer before the fluid started flowing out of the bleeder.

I thought about picking up a bleeder bottle with a cable from Amazon, not the magnet bottle, but I think it is still over priced. At least it has a 16 ounce bottle.

http://www.amazon.com/Genesis-Cable-Blee...s=brake+bleeder

 

[Kestas]

I use a one-man bleeder system. After attaching a clear hose on the bleeder I crack open the bleeder just a bit and pump away. The fluid gets pushed out properly and very little fluid gets slurped back in on the return stroke. Been doing it for years.

 

[eljefino]

I jam an ice scraper between the seat cushion and brake pedal. Then go crack a bleeder and close it. Release the brake pedal and reset the scraper until I'm satisfied.

An added bonus is when I get the sponginess out I can no longer jam my scraper unless I adjust the seat backwards, so I have a point of reference.

 

[Kawiguy454]

+1 on the clear hose and plastic bottle. As long as the hose is submerged in fluid in the bottom of the bottle air wont suck back up. Just make sure the hose doesn't leak at the bleeder.

Loosen the bleeder then give it a few pumps until you see the new fluid color in the hose then close bleeder. Make sure you don't let the reservoir suck air.

I have also used the gravity method with a hose so you can see the new fluid coming out.

 

[Ducked]

I've used a 60 ml hypodermic "enema" syringe to refill the system after it bled dry from a leaking wheel cylinder. Worked but took a while and there was some leakage around the bleed nipple while doing it. You could suck with the syringe as well, to bleed, but I didn't need to do that.

I think the "upward" refill gives less chance of air bubbles. Dry system caused no problems with this car but apparently its major grief with ABS.

If I was doing it again I'd try refilling upward under gravity using the syringe as a high level reservoir, and maybe I'd bleed that way too. You can also buy "enema bags" cheaply that might be better in this role.

Very difficult to find any DIY automotive kit here.

 

[Brad_C]

Quote:
I think the "upward" refill gives less chance of air bubbles. Dry system caused no problems with this car but apparently its major grief with ABS.


Because it pushes a whole load of gunk/sediment out of the cylinder and into the lines/remainder of braking system. It has the potential to trash an ABS unit, an to be honest it can't be good for the seals in the master cylinder either.

There's a reason the whole industry flushes from the top down and it's not just because "we've always done it this way".

 

[Ducked]

Originally Posted By: Brad_C
Quote:
I think the "upward" refill gives less chance of air bubbles. Dry system caused no problems with this car but apparently its major grief with ABS.


Because it pushes a whole load of gunk/sediment out of the cylinder and into the lines/remainder of braking system. It has the potential to trash an ABS unit, an to be honest it can't be good for the seals in the master cylinder either.

There's a reason the whole industry flushes from the top down and it's not just because "we've always done it this way".


Doing this deliberately, I'd do a short "downward" bleed or suck to get rid of any contaminants in the calipers/cylinders (as I did for the other two wheel lines that hadn't bled "accidentally" under gravity.)

Re mc seal damage, I'd have thought if it can handle the pressurization involved in an emergency stop, I'd have trouble breaking it with a 50 cent hypodermic syringe.

If this is likely to be a problem, passive upward refill from a high level reservoir under gravity, as suggested above, would probably limit the applied pressure to non-damaging levels.

I'm not in "the industry", and, as I already stated, I don't have an ABS system. This worked for me. If it gives me any grief in the future, and I survive, I'll let y'all know.

 

[Brad_C]

Originally Posted By: Ducked
Doing this deliberately, I'd do a short "downward" bleed or suck to get rid of any contaminants in the calipers/cylinders (as I did for the other two wheel lines that hadn't bled "accidentally" under gravity.)


Fluid goes in the bottom of the caliper and bleeds out the top. When you do a normal bleed you don't get all the sediment out because some of it does not make it up to the bleed screw. When you do a reverse bleed all that remaining sediment in the bottom of the caliper gets pushed up the hose.

Originally Posted By: Ducked
Re mc seal damage, I'd have thought if it can handle the pressurization involved in an emergency stop, I'd have trouble breaking it with a 50 cent hypodermic syringe.


Nothing to do with pressure. It's the gunk you push up causing erosion of the seals.

I'm happy it worked for you, I'm just pointing out why it's not a technique that is recommended for use (and why). It's a bit like a doctor trying to take out my tonsils by going in through the chest cavity and up the throat. Sure, you can do it but there are better methods which cause fewer side effects.

 

[TFB1]

Originally Posted By: SHOZ
Some brakes bleed easily with the gravity method. Some don't.



This^^^^^

If it has ABS chances are you'll have issues...

After replacing the rear brake hose on my '72 Comet GT I gravity bled the brakes, was a piece of cake...

 

[Ducked]

Originally Posted By: Brad_C
Originally Posted By: Ducked
Doing this deliberately, I'd do a short "downward" bleed or suck to get rid of any contaminants in the calipers/cylinders (as I did for the other two wheel lines that hadn't bled "accidentally" under gravity.)


Fluid goes in the bottom of the caliper and bleeds out the top. When you do a normal bleed you don't get all the sediment out because some of it does not make it up to the bleed screw. When you do a reverse bleed all that remaining sediment in the bottom of the caliper gets pushed up the hose.

Originally Posted By: Ducked
Re mc seal damage, I'd have thought if it can handle the pressurization involved in an emergency stop, I'd have trouble breaking it with a 50 cent hypodermic syringe.


Nothing to do with pressure. It's the gunk you push up causing erosion of the seals.

I'm happy it worked for you, I'm just pointing out why it's not a technique that is recommended for use (and why). It's a bit like a doctor trying to take out my tonsils by going in through the chest cavity and up the throat. Sure, you can do it but there are better methods which cause fewer side effects.


OK, thanks for that explanation. I suppose that could be an issue.

For both these cases, you can cycle the syringe (push then pull) before flushing. This should displace most of the gunk that's easily displacable. It probably wont get rid of all of it, but the immovable residue is perhaps less likely to cause a problem.

I suppose the only way to sure would be to disconnect the MC and back-flush. That's getting to be too much trouble, but it would get the system pretty clean.

 

[buck91]

Did two gravity bleeds this summer with great results. First was the truck in my sig, after replaced all rotors and pads I did 4 wheel gravity bleed (one at a time!) to flush new fluid through the system; went well and fairly quick. Second was my 1996 Mustang. Old fluid came out BLACK and with just new fluid the brake feel drastically improved. But this car took a LOT longer to bleed, I've sure because the MC is much closer to the ground.

Both vehicles are ABS equipped FWIW.

 

[The Critic]

IME, gravity bleeds are inconsistent. I usually gravity bleed each corner for about 5 minutes after using an air-operated vacuum bleeder since I've found that vacuum bleeders usually leave behind a tiny bit of air. What happens is that a small amount of air enters the system thru the threads when you "suck" fluid out of the blender screws.

There's a 50/50 chance that the gravity bleed with remove any air that the vacuum bleeder leaves behind. I have found that following a vacuum bleed with 1 or 2 quick pumps at each corner (2-person manual bleed) will leave a perfect pedal every time.

 

[Lubener]

Recently replaced brake lines to rear and wheel cylinders. I bled the system alone using clear tubing and clear bottle, partially filled w/ brake fluid. While pumping the air and old fluid out, I used a section of pipe wedged between the pedal and seat to hold down the pedal so that I could snug down the bleeder screw, then released pedal to fill up master cylinder. Repeated this several times starting from RR till old fluid was flushed out. When a firm pedal was achieved, I quit. I did not have the patience to gravity bleed. When bleeding, to protect the master cylinder, I did not push the pedal ALL the way to the floor.

 

[Traction]

I use this OTC air powered vacuum bleeder. It is fast, and works perfectly. You can pull a quart of brake fluid through all 4 corners in minutes. Depending on your MC reservoir opening, you can stand a quart bottle up in the reservoir, so you don't have to constantly refill. Don't worry about seeing bubbles coming past the bleeder threads, that is after the fact. Moving fluid through the system quickly bleeds the system. Been using this tool for years, and all by yourself. Just pull the trigger, and watch to make sure you stop, before the bottle overfills is the tricky part. When I built my hot rod I had a completely dry system with separate front/rear master cylinders, one for the clutch, plus brake pressure gauges. Did it all by myself in less than an hour with 2 quarts of fluid.
http://www.amazon.com/OTC-8104-Vacuum-Brake-Bleeder

 

[Traction]

Let me try another link.
https://www.otctools.com/products/brake-bleeder-auto-filler-set